Pump



Juli 17, 1934. P. L. VAUDET ET Al. 1,966,694

PUMP

Filed May 4, 1931 Fig. 2.

ATTORA/f Y5 Patented July 17, 1934 OFFICE PUMP Dullaimnnd Fenland Auguste Guitaut, Paris, France Application May 4, 1931, Serial No. 534.800 In Belgium June 17, 1930 The present invention relates to pumps and, more particularly, to those of the type used for injecting fuel into Diesel and like engines.

It is common practice to provide engines of the Diesel and semi-Diesel type with injecting pumps designed so that the beginning of the injecting period advances when the rate of flow of fuel to the engine increases. In one common type of injector, an inlet port is provided in the walls m of .a cylinder carrying a piston having an oblique head surface and means are provided for rotating the piston so that points situated along the oblique head surface successively come into line with the intake port as the rate of fuel supply varies. However, in injectors of this type, be-

cause of the obliquity of the piston head, the surface of the cylinder is subjected to unequal frictional eifects and becomes easily deformed.

One of the objects of the present invention is to provide a piston, whose head surface is formed by oblique or inclined planes and shaped in such way that the resultant force of the reactions thereon acts along the, axis thereof.

Other objects will appear in the course of the detailed description now to be given with reference to the accompanying drawing, in which:

Fig. l is an axial section through one illustrative embodiment of the invention;

Fig. 2 is a section taken on line 22 of Fig. 1; Fig. 3 is a section taken on line 13- 3 of Fig. 1; Fig. 4 is an axial section through a second form of the invention;

Fig. 5 represents another axial section taken at right angles to the one shown in Fig. 4;

Fig. 6 is an axial section through 9. third form of the invention showing the piston in perspective:

Fig. 7 is a top view of the form of assembly represented in Fig. 8.

Referring to Figs. l'to 3 oi the drawing there is shown a piston a slidably mounted in a cylinder b, the latter being provided with a terminal discharge head d and a lateral intake port e,

a cam c adapted to reciprocate piston a by its 5 rotation. a rack and pinion g coacting with piston a to rotate the latter, and a' cam 1 adapted to act on rack 17 to rotate piston a.

The piston a may be slidably engaged with the' pinion by a key (not shown) and the pinion may 0 be held in engagement with the rack in any suitable manner. For example, the edges of the pinion may be enlarged and extend over the edges of the rack.

It will be noted that piston a is provided with a certain number of grooves and orifices designed to vary the beginning of the pressure stroke and acting to produce a resultant reaction passing along the axis of the piston. To obtain these various effects, the inner end surface of the pis- The hereinabove described assembly operates in the following way: Fuel is fed to cylinder 1) through intake port e and the beginning of the injecting period is varied by rotation of piston a by rack and pinion g and cam I; it will be noted that, when piston a is rotated, surface h successively presents different portions thereof to port e, i. e., the beginning of the injecting period may be varied between any pair of predetermined time limits by rotating piston a (and surface It) through 180; the fuel picked up by surface h from intake port e passes into annular space k and longitudinal grooves l and then into the compression chamber of the pump and out through discharge port (I to the motor when the piston is moved inwardly by cam c; inasmuch as surface 1; is parallel to surface 71., and piston head m is perpendicular to the longitudinal axis of the piston, the thrust on the piston will have a resultant colinear with its axis; when the piston, under the action of cam c, has risen to bring annular groove 1: into alignment with inlet port e, fuel will be delivered to discharge port d via passage q; it will beinoted that annular groove p is limited vertically by horizontal walls, while the begixming of the pressure stroke will vary with rotation of piston a.

In the form of structures shown in Figs. 4 and 5, the assembly above groove p shown in Fig. 1 is replaced by an equivalent assembly composed of a pair of sloping head portions 11. and h symmetrically inclined with respect to the piston axis, and longitudinal grooves r are provided for establishing communication between groove p and the compression chamber of the cylinder. It will be noted that, because of the equal inclination of surfaces h and h, the resultant of the reaction on the piston will have a direction substantially in. line with the axis thereof. This form of pump operates substantially in the same manner as the one shown in Fig. 1 except that variation of the beginning of pressure stroke between any predetermined pair of limits takes place when piston a is rotated through 90 instead of 180". Each of the surfaces 11 and h is a portion of an ellipse.

In the form of piston shownin Figs. 6 and 7, surfaces It and h are provided at the inner end of piston, which are equivalent to the surfaces h and h. which are shown in Fig. 4. In the embodiment shown in Figs. 6 and '1, the surfaces h and h are planar, and the planes in which said surfaces h and h are located, are perpendicular to a plane which passes through the longitudinal axis of the piston. Likewise, the planes in which surfaces It and h are located (in Figs. 6 and 'l) are inclined equally and in opposite direction, relative to a plane which is perpendicular to the longitudinal axis of the piston, so that said surfaces 11 and )1 form portions of ellipses, and they are equal in areas. Annular groove p is here again connected to the compression chamber by means of longitudinal grooves r, and piston a may be rotated (as is also the case for piston-a in Figs. 4 and 5) by assembly f, g shown in Fig. 1 or its equivalent. It will be noted that surfaces It and h in Fig. 6 are positioned so that, as in the case of surface It in Fig. 1, piston a must be rotated through 180 to pass from one limit for the beginning of the injecting period to the other.

What we claim is:-

i. In an' injection pump for internal combustion engines, a cylinder provided with at least one lateral inlet port, a plunger slidably mounted in said cylinder the head of which has two partialelliptical surfaces substantially equally inclined to the axis of the plunger in opposite directions thereof and located in planes passing through a common diameter of said plunger, so that said head cuts off the inlet port atvarious points along the inclined edges of said surfaces if said plunger is turned around its axis, and controlling means for turning said plunger at different angles to vary the time of the closing of said inlet port by said head.

2. In an injection pump for internal combustion engines, a cylinder provided with at least one lateral inlet port, a plunger slidably mounted in said cylinder, the head of which has two partialelliptical surfaces equally inclined to the axis of the plunger in opposite directions thereof and locatedin planes passing through a common diameter of said plunger, so that said head cuts off the inlet port at various points along the inclined edges of said surfaces if said plunger is turned around its axis, said plunger being provided with an annular recess spaced from the head portion, and with a longitudinal groove extending between the latter and said recess, and controlling means for turning said'plunger at different angles to vary the time of the closing of said inlet port by said head. I a

3. In an injection pump for internal combustion engines, a cylinder provided with at least one lateral inlet port, a plunger slidably mounted in said cylinder the head of which hastwo partialelliptical surfaces equally inclined to the axis of the plunger in opposite directions thereof and being located in planes passing through a common diameter of said plunger, said two partialeliiptical surfaces being located respectively on either side of the longitudinal axial plane of the plunger and at right angles to said plane, so that said head cuts of! the inlet port at various points along the inclined edgesof said'surfaces if said plunger is turned around its axis, and controlling means for turning said plunger through different angles so as to vary the time of the closing of said inlet port by said head.

PAUL ILAZARE VAUDET. FERNAND AUGUSTE GUITAUT. 

